Notably, the contrastive learning of \(\mathcal {L}_{cl}\)  has two main effects on CMAC: a) introducing within- and cross-modal instance discrimination knowledge which has been proved crucial and fundamental for \(f_v(\cdot )\)  and \(f_a(\cdot )\)  [1]}, [2]}; and b) bridging the modality gap between \(\kappa _{n}^{a}\) , \(\kappa _{n}^{v}\)  and \(v_{n}\) , \(a_{n}\) .
